Question 404097
Just use all the distributive, commutative laws out there:


5(n + 4) + 9n = (5n + 20) + 9n (distribute property)
              = 5n + (20 + 9n) (associative property)
              = 5n + (9n + 20) (commutative property)
              = (5n + 9n) + 20 (associative property)
              = (5 + 9)n + 20 (factoring out n)
              = 14n + 20 (5 + 9 = 14)